improved and hopefully correct fix for "setting AutomationControl marks session dirty...

Hopefully comment is more explanatory as well.

diff --git a/libs/ardour/automation_control.cc b/libs/ardour/automation_control.cc
index 56fd0e64097f4609c1a49a0b1e148124587a5427..a377aed839aa2b94172f8939faca3d1b270b5bef 100644 (file)
--- a/libs/ardour/automation_control.cc
+++ b/libs/ardour/automation_control.cc
@@ -119,20 +119,41 @@ AutomationControl::set_value (double val, PBD::Controllable::GroupControlDisposi
 void
 AutomationControl::actually_set_value (double value, PBD::Controllable::GroupControlDisposition gcd)
 {
-       bool to_list = _list && boost::dynamic_pointer_cast<AutomationList>(_list)->automation_write();
-       /* We cannot use ::get_value() here since that is virtual,
-          and its return value will/may depend on the ordering
-          of a derived class' own implementation of ::actually_set_value().
-
-          The derived classes generally need to set their own internal state
-          before calling this version, which means that ::get_value()
-          would generally return the *NEW* state, and thus lead to
-          Changed() not being emitted below.
+       boost::shared_ptr<AutomationList> al = boost::dynamic_pointer_cast<AutomationList> (_list);
+       const framepos_t pos = _session.transport_frame();
+       bool to_list;
+       double old_value;
+
+       /* We cannot use ::get_value() here since that is virtual, and intended
+          to return a scalar value that in some way reflects the state of the
+          control (with semantics defined by the control itself, since it's
+          internal state may be more complex than can be fully represented by
+          a single scalar).
+
+          This method's only job is to set the "user_double()" value of the
+          underlying Evoral::Control object, and so we should compare the new
+          value we're being given to the current user_double().
+
+          Unless ... we're doing automation playback, in which case the
+          current effective value of the control (used to determine if
+          anything has changed) is the one derived from the automation event
+          list.
        */
 
-       const double old_value = Control::user_double ();
+       if (!al) {
+               to_list = false;
+               old_value = Control::user_double();
+       } else {
+               if (al->automation_write ()) {
+                       to_list = true;
+                       old_value = Control::user_double ();
+               } else if (al->automation_playback()) {
+                       to_list = false;
+                       old_value = al->eval (pos);
+               }
+       }
 
-       Control::set_double (value, _session.transport_frame(), to_list);
+       Control::set_double (value, pos, to_list);
 
        if (old_value != value) {
                // AutomationType at = (AutomationType) _parameter.type();